The disclosure relates to an optical component.
A technique has been known in which zirconia (ZrO2) is used as a dopant for improving a refractive index of an optical waveguide forming a planar lightwave circuit (PLC) device made of silica-based glass as a material (for example, see Japanese Laid-open Patent Publication No. 2013-210623). In comparison to Germania (GeO2), ZrO2 is a material whose refractive index is high and thermal expansion coefficient is small. Therefore, it is expected to be a material which may reduce a stress remaining in a waveguide while down-sizing a PLC device and an optical component or the like which is provided therewith.
When a core of an optical waveguide is doped with ZrO2 as a dopant, a relative refractive index difference of the core and the cladding of the optical waveguide may be increased in comparison to a conventional optical waveguide whose core is doped with GeO2. Hereby, an allowable minimum bending radius of the core decreases, and thus, down-sizing, cost-reduction, and high density integration of the PLC component or the like which is provided with the optical waveguide may be expected.
However, since confinement of light into the core increases as the relative refractive index difference of the core and the cladding of the optical waveguide increases, a size of the core for achieving a single-mode propagation decreases, and accordingly a beam diameter of the light propagated in the core decreases. Hereby a connection loss may increase between an optical device including the optical waveguide and an optical fiber inputting and outputting light from/to the optical device.
One factor of occurrence of the connection loss between the optical device and the optical fiber may be a pitch shift of an optical fiber array. For example, when using common single-mode optical fibers, nominal values of a pitch shift in an 8-core fiber array (250 μm pitch) and a pitch shift in a 16-core or 32-core fiber array (127 μm pitch) are ±0.5 μm and ±1.0 μm respectively. However, when connecting an optical fiber array having the range of the pitch shift to an optical device whose relative refractive index difference between a core and a cladding is large, a connection loss may increase significantly. Therefore, there is a need for an optical fiber array whose pitch shift is small and connection loss between the optical fiber array and an optical device is small.